The leakage from the pressurized medium in the heating or cooling system via the measuring nipple/nipples is no problem. The measuring nipples have alternative designs having a perfect function, also after long operating times.
There are a many constructions that solve the problem with unintentional leakage from the pressure medium to the environment by finishing the measuring. One example of such a solution is disclosed in GB 2 019 533 A where, according to FIG. 1, a spring-loaded ball 15 tightens the outlet 28 so that the interior overpressure and accordingly the medium don't leaks after completed measuring, also in the case when the operator has forgotten to mechanical close the channel 29 which is connected with the medium. Also U.S. Pat. No. 4,638,668 describes a coupling where the communication from the medium to the measuring hose 32—see FIG. 2—is opened when the measuring hose with its connecting end is mounted on the measuring nipple 2 and in connection with that the communication is opened from the pressurized medium up to the measuring hose 32. Later when the measuring hose is dismounted the communication will again be closed to the pressurized side.